Synthetic and electrochemical studies of some metal complexes of 1,3,5-triethynylbenzene

Abstract

A series of compounds featuring metallic fragments around the periphery of a 1,3,5-triethynylbenzene core have been synthesized. By using several synthetic methods, metallic units such as cis-[RuCl₂(dppm)₂], cis-[OsCl₂(dppm)₂] and [RuCl(η-C₅H₅)(PPh₃)₂] have been treated with the aromatic acetylide ligand to introduce one, two or three metallic centres. Electrochemical studies showed that the bimetallic trans-[HC[triple bond, length half m-dash]CC₆H₃{C[triple bond, length half m-dash]CRuCl(dppm)₂}₂] and trans-[HC[triple bond, length half m-dash]CC₆H₃{C[triple bond, length half m-dash]COsCl(dppm)₂}₂] species undergo two separated one-electron oxidations thus indicating that the central triethynylbenzene unit allows communication between the two peripheral metal subunits. The compounds [(HC[triple bond, length half m-dash]C)₂C₆H₃C[triple bond, length half m-dash]CRu(η-C₅H₅)(PPh₃)₂], [HC[triple bond, length half m-dash]CC₆H₃{C[triple bond, length half m-dash]CRu(η-C₅H₅)(PPh₃)₂}₂] and [C₆H₃{C[triple bond, length half m-dash]CRu(η-C₅H₅)(PPh₃)₂}₃] each show separated one-electron oxidations (though these are less reversible than for the previous compounds mentioned) again demonstrating the electronic communication amongst the peripheral metal centres through the organic linkage. Chemical oxidation has been carried out on the [Ru(η-C₅H₅)(PPh₃)₂]-containing species affording mixed-valence species consistent with those produced by successive electrochemical oxidation.

References

1. U. H. F. Bunz, Angew. Chem., 1994, 106, 1127; Angew. Chem., Int. Ed. Engl., 1994, 33, 1073; F. Diederich and Y. Rubin, Angew. Chem., 1992, 104, 1123; Angew. Chem., Int. Ed. Engl., 1992, 31, 1101; F. Diederich, Molecular Chemistry, NATO ASI Series, ed. J. Michl, Kluwer, Dordrecht, 1996; Modern Acetylene Chemistry, eds. P. J. Stang and F. Diederich, VCH, Weinheim, 1995, p. 443; Nature (London), 1994, 369, 149; T. Bartik, B. Bartik, M. Brady, R. Dembinski and J. A. Gladysz, Angew. Chem., 1996, 108, 467; Angew. Chem., Int. Ed. Engl., 1996, 35, 414.
2. I. Manners, Angew. Chem., 1996, 108, 1712; Angew. Chem., Int. Ed. Engl., 1996, 35, 1602.
3. (a) N. Le Narvor, L. Toupet and C. Lapinte, J. Am. Chem. Soc., 1995, 117, 7129; (b) N. Le Narvor and C. Lapinte, Organometallics, 1995, 14, 634; (c) P. J. Stang and R. Tykwinski, J. Am. Chem. Soc., 1992, 114, 4411; (d) W. Weng, T. Bartik and J. A. Gladysz, Angew. Chem., 1994, 106, 2272; Angew. Chem., Int. Ed. Engl., 1994, 33, 2199; (e) M. Brady, W. Weng and J. A. Gladysz, J. Chem. Soc., Chem. Commun., 1994, 2655; (f) H. B. Fyfe, M. Mlekuz, D. Zargarian, N. J. Taylor and T. B. Marder, J. Chem. Soc., Chem. Commun., 1991, 188; (g) S. J. Davies, B. F. G. Johnson, M. S. Khan and J. Lewis, J. Chem. Soc., Chem. Commun., 1991, 187; (h) M. S. Khan, D. J. Schwartz, N. A. Pasha, A. K. Kakkar, B. Lin, P. R. Raithby and J. Lewis, Z. Anorg. Allg. Chem., 1992, 616, 121; (i) S. L. Ingham, M. S. Khan, J. Lewis, N. J. Long and P. R. Raithby, J. Organomet. Chem., 1994, 470, 153; (j) C. W. Faulkner, S. L. Ingham, M. S. Khan, J. Lewis, N. J. Long and P. R. Raithby, J. Organomet. Chem., 1994, 487, 139; (k) O. Lavastre, M. Even, P. H. Dixneuf, A. Pacreau and J.-P. Vairon, Organometallics, 1996, 15, 1530; (l) I. R. Whittal, M. G. Humphrey, D. C. R. Hockless, B. W. Skelton and A. H. White, Organometallics, 1995, 14, 3970; (m) T. P. Pollagi, T. C. Stoner, R. F. Dallinger, T. M. Gilbert and M. D. Hopkins, J. Am. Chem. Soc., 1991, 113, 703; (n) L. K. Myers, C. Langhoff and M. E. Thompson, J. Am. Chem. Soc., 1992, 114, 7560; (o) Y. Sun, N. J. Taylor and A. J. Carty, J. Organomet. Chem., 1992, 423, C23; (p) L. D. Field, A. V. George, D. C. R. Hockless, G. R. Purches and A. H. White, J. Chem. Soc., Dalton Trans., 1996, 2011; (q) U. H. F. Bunz and V. Enkelmann, Organometallics, 1994, 13, 3823; (r) U. H. F. Bunz and J. E. C. Wiegelmann-Kreiter, Chem. Ber., 1996, 129, 785 and refs. therein; (s) E. Viola, C. Lo Sterzo and F. Trezzi, Organometallics, 1996, 21, 4352; (t) M. I. Bruce, P. Hinterding, P. J. Low, B. W. Skelton and A. H. White, Chem. Commun., 1996, 1009.
4. H. Fink, N. J. Long, A. J. Martin, G. Opromolla, A. J. P. White, D. J. Williams and P. Zanello, Organometallics, 1997, 16, 2646.
5. T. Weyland, C. Lapinte, G. Frapper, M. J. Calhorda, J.-F. Halet and L. Toupet, Organometallics, 1997, 16, 2024.
6. R. R. Tykwinski and P. J. Stang, Organometallics, 1994, 13, 3203.
7. T. J. J. Müller and H. J. Lindner, Chem. Ber., 1996, 129, 607.
8. D. Tzalis and Y. Tor, Chem. Commun., 1996, 1043.
9. M. J. Irwin, L. Manojlovic-Muir, K. W. Muir, R. J. Puddephatt and D. S. Yufit, Chem. Commun., 1997, 219.
10. (a) M. Sato, H. Shintate, Y. Kawata and M. Sekino, Organometallics, 1994, 13, 1956; (b) M. S. Khan, A. K. Kakkar, N. J. Long, J. Lewis, P. R. Raithby, P. Nguyen, T. B. Marder, F. Wittmann and R. H. Friend, J. Mater. Chem., 1994, 4, 1227; (c) I.-Y. Wu, J. T. Lin, J. Luo, S.-S. Sun, C.-S. Li, K. J. Lin, C. Tsai, C.-C. Hsu and J.-L. Lin, Organometallics, 1997, 16, 2038; (d) A. M. McDonagh, I. R. Whittal, M. G. Humphrey, B. W. Skelton and A. H. White, J. Organomet. Chem., 1996, 519, 229; (e) A. M. McDonagh, I. R. Whittal, M. G. Humphrey, D. C. R. Hockless, B. W. Skelton and A. H. White, J. Organomet. Chem., 1996, 523, 33; (f) A. M. McDonagh, M. P. Cifuentes, I. R. Whittal, M. G. Humphrey, M. Samoc, B. Luther-Davies and D. C. R. Hockless, J. Organomet. Chem., 1996, 526, 99; (g) O. Lavastre, J. Plass, P. Bachmann, S. Guesmi, C. Moinet and P. H. Dixneuf, Organometallics, 1997, 16, 184; (h) D. Touchard, C. Morice, V. Cadierno, P. Haquette, L. Toupet and P. H. Dixneuf, J. Chem. Soc., Chem. Commun., 1994, 859; (i) P. Haquette, N. Pirio, D. Touchard, L. Toupet and P. H. Dixneuf, J. Chem. Soc., Chem. Commun., 1993, 163; (j) D. Touchard, P. Haquette, N. Pirio, L. Toupet and P. H. Dixneuf, Organometallics, 1993, 12, 3132; (k) N. Pirio, D. Touchard and P. H. Dixneuf, J. Organomet. Chem., 1993, 462, C18; (l) S. Guesmi, D. Touchard and P. H. Dixneuf, Chem. Commun., 1996, 2773.
11. A. Harriman and R. Ziessel, Chem. Commun., 1996, 1707.
12. W. Beck, B. Niemer and M. Wieser, Angew. Chem., 1993, 105, 969; Angew. Chem., Int. Ed. Engl., 1993, 32, 923.
13. N. J. Long, Angew. Chem., 1995, 107, 37; Angew. Chem., Int. Ed. Engl., 1995, 34, 21.
14. R. Chukwu, A. D. Hunter and B. D. Santarsiero, Organometallics, 1992, 11, 589.
15. M. D. Ward, Chem. Soc. Rev., 1995, 121.
16. M. C. B. Colbert, J. Lewis, N. J. Long, P. R. Raithby, A. J. P. White and D. J. Williams, J. Chem. Soc., Dalton Trans., 1997, 99.
17. P. Sullivan and T. J. Meyer, Inorg. Chem., 1982, 21, 1037.
18. E. R. Brown and J. Sandifer, Physical Methods of Chemistry. Electrochemical Methods, eds. B. W. Rossiter and J. F. Hamilton, Wiley, New York, 1986, vol. 2, ch. 4.
19. J. Amarasekera and T. B. Rauchfuss, Inorg. Chem., 1989, 28, 3875.
20. A. J. Blake, N. R. Champness, R. J. Forder, C. S. Frampton, C. A. Frost, G. Reid and R. H. Simpson, J. Chem. Soc., Dalton Trans., 1994, 3377.
21. R. J. Forder and G. Reid, Polyhedron, 1996, 15, 3249.
22. D. F. Shriver, Manipulation of Air-sensitive Compounds, McGraw-Hill, New York, 1969.
23. A. Togni, M. Hobi, G. Rihs, G. Rist, A. Albinati, P. Zanello, D. Zech and H. Keller, Organometallics, 1994, 13, 1224.
24. J. Chatt and R. G. Hayter, J. Chem. Soc., 1961, 896; M. I. Bruce and N. J. Windsor, Aust. J. Chem., 1977, 30, 1601; M. I. Bruce, C. Hameister, A. G. Swincer and R. C. Wallis, Inorg. Synth., 1982, 21, 79.
25. E. Weber, M. Hedur, E. Koepp, W. Orlia and M. Czugler, J. Chem. Soc., Perkin Trans. 2, 1988, 1251.
26. N. G. Connelly and W. E. Geiger, Chem. Rev., 1996, 96, 877.